There are two problems inherited in glaucoma research: (a) the lack of a dependable glaucoma animal model which can be used to predict the antiglaucoma efficacy of a new drug and (b) the lack of a good experimental method which can be used to study aqueous humor (AH) formation and AH outflow simultaneously, instantaneously and at a constant intraocular pressure (IOP). Specific aims of this study, therefore, include the following: 1. To develop a fast reliable method of studing the rates of AH formation and AH outflow simultaneously in the cat eyes under constant IOP. The changes of AH formation and AH outflow will be monitored instantaneously without time lag. 2. To examine the action mechanisms of antiglaucoma drugs which lower IOP through AH formation decrease, AH outflow increase, or combination of both. Elucidation of action mechanisims of these drugs allows better use of drugs in the treatment of narrow angle glaucoma and secondary glaucoma. 3. To correlate antiglaucoma drugs' efficacy with AH dynamics. This allows prediction of new drugs' antiglaucoma efficacy before human trials. 4. To elucidate the mechanicsm of manifestation of ocular hypertension due to trauma injury and to prevent its manifestation with drugs. It is proposed that autacoids are involved in inflammation and intraocular hypertension induced by trauma. Autacoids antagonists will be used to prevent their occuring. 5. To investigate the circadian variation of IOP. The spontaneous diurnal IOP variation in open-angle glaucoma is an important but poorly understood phenomenon. Attempt will be made to elucidate whether the variation in IOP is due to change in AH formation or AH outflow.